Fishing tool



Filed July 3, 1959 P. M. REA

FISHING TOOL June 9., 1942.

M Q 1 1L,

,2 s eets-sheet 1 2 Sheets-Sheet 2 [villa/111471471? June 9, 1942. P. M. REA

FISHING TOOL- Filed July 3, 1939 Patented June 9, 1942 UNITED STATES PATENT OFFICE 4 Claims.

My invention relates to fishing tools for removing from wells, cylindrical objects such as, drill stem, tubing, and the like, and more particularly to fishing tools of the type commonly known as an overshot.

Overshots are designed to be passed over the exterior of the pipe or fish and to engage its periphery, in contradistinction to the spear type which is adapted to pass into the fish and engage the wall of its bore.

In most types of overshot, radially sectioned pipe slips seated upon tapered slip seats formed in the bowl or housing are utilized as the medium for engaging the fish. Due to the fact that the annular space lying between the well casing and the fish is in most instances very limited, and due to the fact that the overshot must operate in this annular space, others have heretofore resorted to a plurality of vertically spaced tapered slip seating surfaces, and have provided slips having vertically spaced outer tapered surfaces conforming to the taper of the slip seating surfaces. This practice has. made it possible to construct the slips with a minimum of wall thickness and consequently the wall thickness of the bowl could be left sufiiciently thick to pass over the fish and yet have the strength to withstand the bulging action of the slips against the slip seats when the fish is engaged and attempt is made to raise it. in the well.

U. S. Patent No. 1,234,041 to Knapp discloses a slip assembly in which the member l2 has two vertically spaced slip seating surfaces I4 which seat the slip segments. This principle has recently been applied to fishing tools in order to save wall thickness and yet distribute the outward thrust along a greater surface of the bowl as above described; Patent No. 2,128,430 to Pryor also shows an application of this principle to an overshot, but uses his slips to catch fish of different diameters. It is pointed out that should a single long tapered slip seat be used, for instance as long as Pryors two seats, the wall of the bowl would have to be much greater inv thickness than is necessary when two spaced. seats are provided. Also, that the permissible diameter of the fish. is limited by the inside diameter f the slips when they are at the upper end of their permitted travel.

The prime object of the present invention is the provision of an overshot designed to per-' mit an increase in the thickness of thebowl wall without increasing its outside diameter, thus obtaining greater strength.

Another object is the provision of a tool of this class in which the slip segments are positively held in operative relation to the bowl and to each other.

A further object is to provide an overshot which is releasable from the fish should the fish be found to be immovable.

Other objects of the invention are to provide a tool of this class which is simple in, construction and assembly; which is so designed that its lifting load is evenly distributed over a considerable space in the bowl, yet the slips of which are extremely thin so as to permit operation in confined annular spaces; which is durable; and, which will be efiicient in accomplishing all of the purposes for which it is intended.

In the drawings:

Figure 1 is an elevational View of the complete tool located within a well casing, and showing a fish about to be engaged thereby;

Figure 2 is an elevational sectional view of the tool with the fish engaged therein;

Figure 3v is a horizontal sectional view taken substantially along the line 33 of Fig. 2, the fish having been removed;

Figure 4 is an elevational sectional view of the bowl, slips, and key member, and taken substantially along the line- 44 of Fig. 3;

Figure 5 is an elevational sectional view of the bowl with, the slips and key member removed, and taken substantially along the line 55 of Fig. 3; v

Figure 6 is a perspective view of one of a pair of slip segments used in the bowl; and,

Figure 7 is a perspective view of the key member for positioning the slip segments radially within the bowl.

Like characters of reference designate like partsv in all, of the figures.

In the accompanying two-sheet drawing, Fig. 1 illustrates the manner in which the overshot is installed for use in a well. The reference numeral 10 indicates as a Whole a tubular body or bowl to the lower end of which is threadcdly connected a tubular guide shoe ll having an open lower free end for passing over a fish. In the drawings, the fish is illustrated as being the upper end of a section of usual upset drill stem I 2; but the device may function to engage other cylindrical objects. While the shoe H is illustrated as being only a usual tubular guide, it may if desired be supplanted by other types of shoe such as a usual wall-hook, milling tool, or the like, not shown.

The upper end of the bowl I0 is threadedly connected to an upper tubular body section I3 As may best be seen in Fig. 5, the inner surface or wall of the bowl I is provided with a plurality of vertically spaced, downwardly and inwardly tapering, annular slip seating surfaces I9, 20 and 2|. The slip seating surfaces are integral with the wall of the bowl l0 and extend slightly inwardly beyond the bore of the bowl, which bore is indicated by the numeral 22. A

pair of oppositely disposed vertical slots, one of.

2B which have their outer surfaces tapered to conform to the taper of the slip seats, and which have threads 21 on their inner surfaces. Similar ends of the ribs 24, 25 and 26 are rigidly connected together by vertically disposed bars 28 which, when the segments are installed within the bowl l0, rest within the slots 23 thereof. It may readily be seen that when the slip segments are disposed within the bowl, the bars 28 will contact the sides of the slots 23 and prevent rotation of the slips within the bowl.

As clearly shown in Figs. 3 and 4, the combined width of two of the bars 28 is less than the width of one of the slots 23, and consequent; ly, in order to hold the slip segments outwardly upon the slip seats, it is necessary to provide a means for holding the adjacent bars 28 apart. This is done by two legs or keys 29 which depend from an annular follower 30 (Fig. '7) The follower 30 has an exterior upwardly facing shoulder 3| for seating the lower end of a helical compression spring 32. The section l3 when screwed into the bowl ID contacts the upper end of the spring 32 and urges it into compression. Consequently the spring exerts a downward force upon the follower which in turn urges the slip segments downwardly in an obvious manner. However, downward movement of the slips is limited by the amount of lateral play of the two bars 28 and the key 29 within the slots 23. This play is suificient to permit the slip segments to move inwardly toward each other a sufiicient distance for the threads 21 to engage the fish l2, but is not sufficient to permit the slip segments to move downwardly off their seats.

A resilient sealing ring 33 is provided in the lower end of the bowl In in order to seal between the exterior of the. fish l2 and the wall of the bowl. The ring 33 makes it possible to circulate a fluid downwardly through the string I6, the sub I5, the section I3, through the bowl In, and into the fish, so that the fish may be washed loose from the casing or well, if desired.

In assembly, the slip segments and follower 30 are merely dropped into the bowl and the spring 32 is placed upon the shoulder 3|. The section I3 is then screwed into the bowl l0, and the device is then ready for installation on the lower end of a drill stem string.

In operation, when the tool is lowered over the fish, it contacts the slip segments and raises them sufiiciently toenter the bowl until its upper end contacts the lower end of the follower 30. This stops further downward movement of the tool. The tool is then raised, and

since the spring is urging the slip segments in a downward direction, the threads 21 of the slips frictionally engage the fish.

Since the slip segments are made of harder metal than the fish, they cut into the fish, and the greater the upward pull on the bowl, the tighter the gripping action of the slips due to the tapered seats.

If, after the fish has been engaged by the slips, it is desired torelease the same and remove the tool, the drill stem string is lowered sufficiently torelease the gripping action of the slips, and the tool is then rotated to unscrew the slips from the fish.

It is thought that the apparatus shown and described herein will function within a narrower annular space |8 to support more weight than any previously conceived overshot of the slip type. The present tool is both releasable and circulating, and has proven under tests to accomplish all of the objects for which it is intended.

Obviously the slot and key arrangement may be employed in connection with an overshot having a single slip seat with segmental slips thereon.

I claim:

1. In a fishing tool: an overshot bowl; a plurality of vertically spaced tapered slip seats in the bowl and having vertical slots intersecting them; slips upon the seats formed in segmental sections, each section comprising a plurality of substantially semi-circular fish engaging members having their exterior surfaces tapered to conform with said seats; vertically disposed bars holding the ends of the members in spaced relation and lying within said slots; and, a tubular follower slidably disposed within the bowl above the slips and having legs extending downwardly into the slots and between the bars, said legs adapted to hold the slip segments upon their seats.

2. In a fishing tool: an overshot bowl; a plurality of tapered slip seats vertically spaced therein, said seats intersected by transverse slots of a depth not greater than the thickness of the seats; vertically spaced segmental pipe gripping slips slidably disposed upon the seats; a key in the slots and between the adjacent ends of the slip segments for holding them on said seats; and, means integral with the key and urged to bear upon the slips for limiting movement of the key vertically coincidental with vertical movement of the slips in the bowl;

3. As a sub-combination in overshot fishing tools, an overshot bowl including: a tubular body for enveloping a fish; a plurality of vertically spaced tapered slip seats formed in the bore of the body; and, longitudinally extending slots intersecting said seats, said slots being of a depth no greater than the thickness of said slip seats.

4. In an overshot fishing tool, the combination with a bowl having a plurality of vertically spaced slip seats, and a similar plurality of vertically spaced interconnected segmental slips adapted to seat upon said seats, of a slip follower adapted to bear downwardly upon the uppermost slip segments, including: a tubular sleeve; and spaced depending legs integral with the sleeve to reside between adjacent ends of said slip segments to maintain the same upon their seats.

PHILIP M. REA. 

